A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section.
Case structures support sections of the engine and are joined at flanged connections. The turbine section will typically include a high pressure turbine and a low pressure turbine that each are disposed within separate case sections attached to each other. In some engine configurations a mid-turbine frame is disposed between the high pressure turbine and the low pressure turbine and is supported by a separate case structure disposed between cases for the high pressure turbine and low pressure turbine sections. The mid-turbine frame provides support for rotating engine components and includes support structures that extend radially outward to the mid-turbine case structure.
Additional structures add cost, weight and complexity and therefore it is desirable to develop more efficient case structures.